Yes, in Jain Dharma you can take a temporary vow for a specific period like 1 hour, 3 hours, half a day, or any fixed duration to not eat or drink anything.

This is commonly done as a form of sankalp, upvaas, or niyama, depending on the purpose and tradition.

A few points:

• It should be taken with clear intention and firmness.
• During that time, you should not eat or drink anything if that is the vow you have taken.
• It is best to keep the vow within your ability and with proper awareness.
• In Jain practice, such short vows are also useful for self-control, tapas, and spiritual discipline.

If the vow is only for a few hours, that is still meaningful if observed sincerely. The important thing is bhav — the inner भावना of restraint and purity.

In Jain terms, this is a valid form of limited fasting or restraint, as long as it is done honestly and respectfully.